Migrate from setup.py to pyproject.toml

[pefoley2]

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Based on https://setuptools.pypa.io/en/latest/userguide

Proposed changes

Migrate configuration from setup.py to pyproject.toml, but leave a stub setup.py to avoid breaking setup.py test and friends.

Brief description of rationale

Setuptools is discouraging direct usage of setup.py https://setuptools.pypa.io/en/latest/userguide/quickstart.html#transitioning-from-setup-py-to-setup-cfg

[coveralls]

coverage: 80.194%. remained the same when pulling 6d33f0c1b7d0cc09427bf70bf13620034a857ff4 on pefoley2:dev into d9ad6ad2a2e08fc2d335fb8fd3973711545ad444 on tjcsl:dev.

[NotFish232]

Closed in favor of #1648